Re: [PATCH v7 7/7] Documentation: kernel-parameters: Add DEVNAME:0.0 format for serial ports
From: Dhruva Gole
Date: Thu Mar 28 2024 - 02:06:07 EST
Hi Tony,
On Mar 27, 2024 at 12:59:41 +0200, Tony Lindgren wrote:
> Document the console option for DEVNAME:0.0 style addressing for serial
> ports.
Thanks, this will really add in more context for people unaware.
>
> Suggested-by: Sebastian Reichel <sre@xxxxxxxxxx>
> Signed-off-by: Tony Lindgren <tony@xxxxxxxxxxx>
> ---
> .../admin-guide/kernel-parameters.txt | 19 +++++++++++++++++++
> 1 file changed, 19 insertions(+)
>
> diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
> --- a/Documentation/admin-guide/kernel-parameters.txt
> +++ b/Documentation/admin-guide/kernel-parameters.txt
> @@ -785,6 +785,25 @@
> Documentation/networking/netconsole.rst for an
> alternative.
>
> + <DEVNAME>:<n>.<n>[,options]
> + Use the specified serial port on the serial core bus.
> + The addressing uses DEVNAME of the physical serial port
> + device, followed by the serial core controller instance,
> + and the serial port instance. The options are the same
> + as documented for the ttyS addressing above.
> +
> + The mapping of the serial ports to the tty instances
> + can be viewed with:
> +
> + $ ls -d /sys/bus/serial-base/devices/*:*.*/tty/*
> + /sys/bus/serial-base/devices/00:04:0.0/tty/ttyS0
> +
> + In the above example, the console can be addressed with
> + console=00:04:0.0. Note that a console addressed this
> + way will only get added when the related device driver
> + is ready. The use of an earlycon parameter in addition to
> + the console may be desired for console output early on.
Reviewed-by: Dhruva Gole <d-gole@xxxxxx>
--
Best regards,
Dhruva